Bi-annual US dollars 1987-06-30 10 1987-12-31 15 1988-06-30 22 1988-12-31 36 1989-06-30 47 1989-12-31 60 1990-06-30 59 1990-12-31 60 1991-06-30 81 1991-12-31 75 1992-06-30 101 1992-12-31 91 1993-06-30 228 1993-12-31 216 1994-06-30 245 1994-12-31 349 1995-06-30 332 1995-12-31 434 1996-06-30 479 1996-12-31 449 1997-06-30 504 1997-12-31 668 1998-06-30 880 1998-12-31 810 1999-06-30 1044